Electronic structure of amorphous transition metal alloys

Abstract

sd hybridization effects are studied for disordered systems using a tight-binding model and a random phase approximation. Using this model, we present calculated electronic densities of states of transition metal amorphous alloys of the type Cu x ( TM) 100− x ( TM ≡ Ti, Zr or Hf) across the compositional range, taking into account charge transfer and possible chemical short-range order. We show that chemical short-range order occurs for some given range of compositions, depending on the alloy considered. We compute transport properties such as resistivity and Hall effect and show that sd hibridization is essential to understand the sign reversal of the Hall effect which occurs in these materials. We also study the case of a collection of d resonant states coupled to an sp conduction band. This will be applied to understand the electronic properties of quasi-crystalline AlMn quenched alloys.